


Pyrophilia

by Dragoncurl



Category: Undertale (Video Game)
Genre: Gender-neutral Reader, I did my best, Other, and again my one-shot sin is surprisingly long, can you tell i like the fire man yet, im sensing a trend, or at least i hope so
Language: English
Status: Completed
Published: 2017-08-14
Updated: 2017-08-14
Packaged: 2018-12-15 11:56:53
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,490
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11805513
Author URL: https://archiveofourown.org/users/Dragoncurl/pseuds/Dragoncurl
Summary: After working (and living) with Grillby for a year, you realize you have a MASSIVE crush on the elemental.Much to your surprise, you find out he reciprocates it.





	Pyrophilia

If someone had told you a few years ago that humans aren't alone in the universe, let alone on Earth itself, you would've laughed in their face. Now, though, you'd just go 'well, yeah'. Your boss is a monster, after all, and for once you don't mean that in the metaphorical sense of the word.

Despite the mess of the first year right after monsterkind revealed itself from within Mount Ebott, which stands just a few miles away from your hometown, the integration of monsters into human society has been slow but peaceful. There is a vast and thriving community around and on the mountain itself, right up to the always-snowy peak, and several monsters have even moved into your city, the closest to the mountain. They're few, but you know just about all of them by sight. You work at the only monster-run establishment in the city as the only human employee, a quaint little place called Grillby's.

A while ago, your situation was... less than ideal. You'd been juggling retail and fast-food jobs to try and keep yourself afloat, but you were working yourself to the bone almost every day of the week and could barely break even with your bills. Dropping out of college had pretty much guaranteed that your parents wouldn't give you a single penny in help. You'd shown up on Grillby's doorstep out of desperation, and perhaps just a hint of curiosity about monsters in general.

To your surprise, Grillby not only hired you, but insisted that you move into the back of the bar with him until you had enough money to get a place of your own without having to work yourself to death. You tried to turn down the offer, it just felt weird living in the same place you'd be working in, but the promise that Grillby would cover all living costs was what convinced you. At the time, you told yourself you'd get a place of your own again in a few months, probably.

That was a year ago.

The thought sometimes nags at the back of your mind, but honestly, by now Grillby is less like your boss and more like your partner when it comes to running the bar. The only thing he does that you don't is cook, but you share responsibility for everything else. You're even getting pretty damn good at reading him despite his almost total lack of an actual face; he only has the eyes behind those square glasses, which he's told you are just for looks.

You've gotten so used to Grillby's presence you don't even know how you lived without him. At night, after you both close the bar and clean up, you eat dinner together. Most of the time you just leave the TV on in the background and bounce between talking to each other and answering questions about one another's worlds. You've seen enough monster television to get sick of that damn eyesore of a robot, but just about anything else is good. You spend a few hours together, sometimes argue playfully about who's doing the dishes that night, and head to bed in your respective rooms. It's nice, and easy, and comfortable. You had a decent roommate during the short few months you tried grinding your way through college, but that can't hold a candle to your relationship with Grillby.

It catches you off-guard.

It's just a regular night. You and Grillby close the bar, clean, eat, talk, say good night. Business as usual. Except that you're woken up in the middle of the night by a very, _very_ vivid dream involving you, Grillby, and a whole lot of sex. Your whole body feels uncomfortably wound up and the bedsheets are like an oven, but you just lay there, shocked, a little breathless.

Almost like a movie waiting to start, your newly-awakened mind begins to conjure up memories from your time with Grillby. You start to realize how good he looks, all sharply-dressed in the same uniform that never seems to sit quite right around you. In your mind's eye you see him mixing drinks with fancy maneuvers, throwing bottles and mixers spinning up into the air, the fabric of his sleeves straining over toned muscles that you've only gotten to see a handful of times over the past year. You remember how his flaming hair felt like heated silk on your fingers when you asked to touch it, how his skin is almost always on the exact boundary between too hot and _just_ hot enough for the heat to soak into your very bones with the lightest sting. You think about his laugh, about how much you love it when you manage to break his usual stoic demeanor and make his mouth form, a jagged, lipless smile with fangs that shift in shape and size like the fire of his hair.

... _fuck_.

You have a serious crush on your boss.

For the next few weeks you try to bury those lewd thoughts in the back of your mind, but it's useless. Every time you see Grillby, every touch of his skin no matter how light, every drink you get to watch him mix, every laugh, every word like the crackling whisper of burning wood, it's a flame to make your heart melt like ice. You have more wet dreams, each more wild than the last, and one of them is so lengthy and detailed you can barely look Grillby in the eye the next day.

That night, when you're watching TV together in silence, you're completely zoned out. Your eyes are on the screen but your mind is furiously trying to think of anything _but_ wanting the literally-and-metaphorically-hot fire elemental sitting next to you to bend you over and fuck you senseless.

Then a fiery hand touches your arm and you jump and yelp.

Aaand there goes the blushing, of _course_ . That goddamn heat just sets your blood on fire and it does not help your overactive mind _at all_ , and you have to force yourself to look away so Grillby doesn't see the intense blush across your cheekbones, but...

He catches your jaw. And turns your head to him. And studies your face. You see his eyes very clearly linger on the bloom of red on your skin before they meet yours, and there's... _something_ in his gaze, but you can't tell what it is, you're way too rattled. You just sit there, frozen yet melting inside at the same time, with his fingers wrapped around your jaw making the bone feel like a lump of hot metal under your skin.

And then Grillby leans closer.

And you silently start to panic.

And you're almost blinded when his mouth finds yours, and your breath locks up in your throat.

You start to respond out of sheer reflex, until your brain grinds back into gear and you wrench yourself away, breathless.

What the _fuck?!_

That's what you _want_ to say! But you can barely stutter out a half-syllable before one of Grillby's flaming fingers comes to rest across your lips. He's smiling, actually _smiling_ with his zig-zag mouth plainly visible, and he reaches up and pulls off his glasses and sets them down on the coffee table.

He kisses you again. Both his hands cradle your face, enveloping it in warmth, and you just _melt_ . You kiss him back eagerly, wrapping your arms around his broad shoulders, threading your fingers through his flame hair, losing yourself completely in the thick aura of heat around him, on the feel of his lips on yours, the sting of his lava-like tongue in your mouth. You've been dreaming about this for almost a month, but it feels so much _more_ than you could've imagined and you don't ever want it to end.

But it has to. You run out of breath and have to surface with a loud gasp, but by the time you do you're lying flat on your back with Grillby on top of you, propped up on his elbows; the heat is so intense you might start sweating just from that, you feel like you're burning up in your own clothes.

You stare up at Grillby in utter disbelief. He's still smiling. You're too breathless to speak, you just mouth a silent question, something that can't decide it it's a 'what' or a 'why'.

Grillby's response is to reach for the remote and turn off the TV, and then he looms over you again.

"I've found you attractive from the moment I first laid eyes on you."

You can't believe your ears. That was more than a year ago! Has he been having thoughts about you this whole time and you never knew?!

"Don't get me wrong, I really did want to help you. It was clear how desperate you were. The view was just... a pleasant bonus."

Grillby starts running his thumb back and forth across your cheek. The heat sends sparks racing all over that side of your face.

"But I've noticed how your behavior changed this past month. You've been watching me more intently, I've seen it. And that blush just now..."

You're starting to feel uncomfortably hot in your own clothes in a quite literal sense. It's getting uncomfortable. You can't help but fidget slightly, though Grillby either doesn't notice or doesn't care because he just keeps smiling.

"Well. The kiss said everything. You want me, _badly_ , don't you?"

You just nod fervently. Your nerves are still too frazzled and your breath too thin to say much, but _god yes_ , you want him. You want to see the toned body he keeps hidden under his formal attire, run your hands all over it, see what his fire-skin tastes like, what it looks and feels like pressed up against your own. You want to bask in his light and heat like he's the fucking Sun and you're on vacation at a beach smack-dab on the Equator.

Your eagerness must show on your face because Grillby's expression shifts, though you can't really tell what exactly he's thinking. He starts to move, sliding his knees under your thighs as he pushes himself up so he can sit on his ankles with your legs around his waist. His crotch is so close to yours you can almost feel it, there's barely an inch between you, if even that, and the area between your legs explodes in heated tingles that spark up your spine like fireworks. The heat isn't nearly as intense like this, but you still feel overheated in your own clothes.

You don't even have to do anything, however, because Grillby's broad, strong hands come to rest on your thighs and slide in unison up to your hips. His fingers worm under your shirt, and every touch feels electrified, injecting more fire into your blood, more sparks across your entire body. His thumbs hook over the hem, and as his hands slide up your torso Grillby pushes the garment up, and you lift your back so he can go all they way to your chest and past it to your collarbones. There he pauses and wraps his hands around either side of your ribcage, and you lift your head and arms to let him pull the shirt up and off and drop it in a heap on the floor.

You don't even wait for Grillby's hands to come back down. You hurry to sit up and throw your arms around his neck, fingers in his hair, mouth against his for a hungry, lustful kiss; he responds without hesitation. This time you're the one pushing against him, making him lean back, but he never lets himself lie down. Again you surface from the kiss only when you run out of breath, but you don't stay idle this time. Your fingers skitter up to the open collar of his dress shirt- he takes the bowtie and vest off when he's not working- and start undoing the buttons, but every single one takes you at least three tries since he keeps sliding his fingers along your sides and it's making you _very_ distracted.

Soon, though, you're both bare from the waist up, and you hug him tight to your front and finally get the full effect of his magma skin and it is _glorious_ . Hot enough to _almost_ , but not quite, make your flesh sting, right at the boundary where your body would start complaining about the excess heat. It's exactly how you like your showers, and you moan and kiss him a third time and this time he does lie back with you on top, and you try grinding against him but he's so much taller than you you only succeed in dry-humping his lower stomach, and Grillby laughs! He breaks away from the kiss and _laughs!!!_

You're about to protest when he takes your head between his hands and steadies it, and looks directly into your eyes. He's burning a little hotter now, a little brighter, his flames shifted from the usual dull orange to a more vivid gold color and a pale yellow core, so it's a little hard to maintain eye contact.

"Easy now. Let's not get ahead of ourselves, hm? I know you want this, but you won't enjoy it to it's fullest at this rate. Just slow down a little. Take a deep breath."

Your first instinct is to argue, but...

He's right, isn't he? You've been fantasizing about this for like a month, you should take your time. Your eyes slide shut, and you have to wait a few moments until you can draw in a proper deep breath.

"Keep going."

Grillby releases your head, but you stay propped up on your elbows over him, breathing deep and slow, feeling the hot air rise from his body and curl around yours, smelling a faint hint of firewood and brimstone coming off him. His hands settle on your waist and stay there, and your lower bellies are touching, but this pause to just breathe and wind down does help. Your heart is still racing, but not at the frenzied pace from before. There's less fireworks in your blood and bones and brain. The haze of lust clears considerably.

When you open your eyes again, you find a much more satisfied smile splitting Grillby's otherwise featureless face.

"There. Much better."

He strokes your cheekbone with his thumb again. You smile at him too. You lean down and give him a much more chaste kiss, then sit up between his legs just like he did earlier between yours. You start to explore. Grillby doesn't seem to have collarbones, or at least no noticeable bumps at the base of his neck, but he does have pecs that you splay your hands across, and abs that you trail your fingers between and over, and muscular arms that you squeeze experimentally around the biceps. He seems sort of amused now, just lying back and watching you. The texture of his skin is strange, perfectly smooth and yet very soft.

Your hands reach the hem of his pants. You glance back up for confirmation, and he gives you a silent nod. You undo the belt, button, and zipper, and fold the two halves to the sides to find nothing at all underneath! No underwear! It's just his fire-gold flesh, continuing unhindered under the fabric. You tentatively stroke the tips of your fingers across his... pubic mound? You guess? You kinda feel like that name's just for female parts, but whatever, you're not a biologist.

Grillby lifts his hips under your hands. You look back up at him, but he's just got that amused smirk now. You know what to do, though. Your hands move to his lower back, right above his pants, but rather than grabbing the hem you just splay your fingers against his skin and slide them down, pushing his pants out of the way and getting two very nice handfuls of his butt in the process.

You hear Grillby chuckle quietly.

Before long his pants are on the floor, and suddenly he's fully naked right in front of you, with his legs around your waist and his crotch in plain view. He's at full mast already, and he's _huge_. Of course he is, he's so much taller than you! He'd have to dip his head down just to touch his chin to the top of your head, and you're not exactly short either. You can't help a slight gasp of disbelief.

You glance back up, and again Grillby just gives you a nod. Very carefully, like you're handling a tiny, fragile animal, you wrap your hand around him, and here the touch does actually sting, his member feels hotter than the rest of his body, and you must've winced because suddenly the temperature drops, and when you look up Grillby's still watching you, but he remains quiet. You return your attention to his member and rub your thumb up and down on the underside, then loosen your fist and move it to the head, feeling the ridges, curling your palm around it.

Grillby doesn't moan, exactly. It's more like a very low, very deep hum that seems to emanate from the core of his chest, but you take it as a good sign.

You scoot back and lean forward, until you're inches from his length with your hand around the base. One last glance up for confirmation, and you stick your tongue out and give the underside of his member an experimental lick. He tastes like nothing you've ever tasted. You can't even put it into words properly. It's hot, of course, but sort of spicy? It's strange, but not unpleasant at all.

Again, Grillby doesn't moan, but the hum is stronger, more forceful, and you see one of his hands move just a little bit lower on his stomach.

You give him another lick, then another, then swirl your tongue around the head, and each time his little hum gets louder until he finally does moan, and his fingers thread through your hair gently. You lean into his palm, then release him and climb over him back up to eye level so you can kiss him again. While you do, you feel him open your pants single-handed, and then his fingers are probing into your underwear, palm flat on your skin as the digits creep lower with every passing second, and at first you just whimper quietly, but then you have to wrench your mouth free so that a moan can explode out of you, and your hips grind into his hand almost by reflex.

Goddammit, you still have your pants on! You should've let him take them off! Curse your horny lack of foresight! You force yourself to pull away and scramble to your feet, and thankfully Grillby holds one of your hands to help steady your wobbly knees. Standing next to the couch, you pull and yank and tug until you can kick both your pants and underwear away, and then you can finally climb over him and straddle him, naked, feeling his heat directly between your legs.

With your hands splayed across his chest again, you waste no time in scooting back until you can grind against his member. Grillby actually _groans_ , both hands firmly planted on your hips, almost as if guiding your movement very subtly, and you actually feel his temperature waver under you, like his body is trying to heat up but he's fighting against it. Grillby is starting to burn so bright you're actually starting to see his light _through_ your hands, making your flesh glow red around the vague outline of the bones in your palms, and his fire's gone up to a bright yellow with a white core that makes his eyes a little hard to make out.

When you feel ready, you move one hand down to grasp him and guide him to your entrance. You rub against him a few times, drawing a quiet little gasp from Grillby, and then you start pushing down. Agonizingly slow, the head of it invades you, and you have to stop because holy fucking shit, he's _huge_. You've never had anything quite this girthy inside you. You're forced to just sit there, waiting for your body to adjust, but thankfully Grillby does his best to help with his hands between your legs, and you moan and roll your hips into his touch.

It's with the help of his adept fingers flooding your brain with bliss that you keep lowering yourself, inch by painstaking inch, moaning and gasping all the way until, to your own surprise, you can't go any further. There's still at least half an inch of him to go, maybe even more, you can't tell, and yet you can't go any further. You try a few times, carefully, but your body just ran out of room. Grillby's just too big.

You look up at him, but he doesn't seem bothered at all. His mouth's hanging open, just a little gap in the fiery fangs. Grillby actually places one of his hands between you with his fingers framing the base of his member, to close the gap and make sure you can't go any farther down. You try to laugh, but all that comes out is a single breath of a chuckle that quickly trails into another moan when Grillby's free hand keeps working between your legs.

With a continuous streams of moans dripping from your lips you start to roll your hips. Both of Grillby's hands are occupied, so you have total freedom in your movement, and you keep your hands planted on his chest, glowing red with his light, as you slowly go from rolling your hips to moving them up and down. You're watching him, watching his fire ebb and flow, feeling his chest rise despite your weight while he breathes and moans with you, always at a much lower volume. His gaze is on his hands at first, but then he locks eyes with you, and then you're forced to squeeze your own shut, both from his sheer brightness and the almost overwhelming sensations radiating from below, it's so much your hands clench against his chest and you hear a groan at your nails scraping his magma-skin.

Even through your eyelids you see his light, filtered into an intense orange. You keep moving, up, and down, and up, and down, shifting backward when you lower and sliding forward when you rise in a circular motion. One of his hands trails up your front and clasps around your shoulder and pulls you down for a kiss, and soon you're on top of him again, alternating between messy kisses and loud moans as he takes over the movement. Grillby never pushes deeper than you can handle, but he starts picking up the pace, and you feel his heavy, heated breaths stream past your ear as he does, his quiet little moans whenever one of them slips out. You cling to Grillby as he speeds up, little by little. Your moans become accompanied by wet noises from below and broken curses under your breath, and soon your whole body is being rocked by his thrusts.

But just for a little while.

You don't know who goes off first. All you know is that suddenly your breath clogs your throat and your whole body seizes up as a flood of heat washes over your insides, and Grillby buries himself as deep as you can take him and his arms and hands tighten around you along with yours around him, and for a few seconds you're both trapped in each other as your mind goes blank, like the Fourth of July going off all at once inside your skull and you vaguely register Grillby making a wordless vowel-like noise with his mouth next to your ear.

...

And then you crash back down to Earth, utterly spent and completely limp over him.

You're both breathing hard. Grillby's chest is actually moving you up and down a little. You have your forehead resting on the side of his neck. For a while you just lay there, breathing, letting your galloping heart and heaving chest slow down. When you blearily crack your eyes open you find that Grillby's body has dimmed considerably, ever lower than his usual color. He's closer to a sort of terracotta shade with an orangey core.

You prop yourself up on your arms and look down at him with a codeine smile. He strokes his fingers across your cheek, then through your hair, and you share another little kiss.

"I hope I lived up to your expectations."

You just laugh and tell him he did. He helps you rise high enough for him to slip out of you, then sits up to keep you steady as you get to your feet. Goddamn, that was amazing, but you feel way too sticky for comfort. And while you're standing in front of him, holding his hands while your knees stop shaking, you realize something.

That heat in your gut is still there. It's strongest down below, but it's reaching up all the way to your lungs, like a fading miasma of temperature inside your whole torso. You frown and put a hand to your stomach, then look at Grillby questioningly.

"Lingering magic that has permeated your body. I've heard humans can have some... _unique_ reactions to sex magic, but it should fade soon."

Sex magic? That does sound right, now what you're thinking about it. Grillby's made of like, fiery stuff, you guess he wouldn't have normal cum.

Once your legs feel steady, you make your way to the bathroom and rinse off the layer of sweat sticking to your body; Grillby leaves your clothes on top of the toilet lid while you're cleaning up. You feel a little bit sore, but it's nothing worrying. You get out, dry yourself, get dressed. It's earlier than the time you normally go to sleep, but you're still feeling pleasantly lazy, and this warmth in your pelvis feels like it's making your joints all loose.

Grillby doesn't sleep, but he still accompanies you to your room and folds up your clothes while you change and even has the _gall_ to tuck you in! If you weren't so drowsy you'd probably complain at him. Instead, you just get comfortable under the sheets, and Grillby kneels down next to your bed and dims his fire to a dull red while he strokes your hair. You sleepily joke you don't need a night light, but he doesn't bother acknowledging that. He just keeps combing his fingers across your scalp.

"Sleep. We can chart our path together tomorrow."

You can just barely see his dulled glow through your heavy eyelids. You mumble something that's supposed to be at least close to a 'good night'.

"Good night."


End file.
